Google is changing Sitelinks, the links below a search result with access to other pages of the same site.
Changes include: - Sitelinks are now full-size links with a URL and one line of snippet text. - Links have increased from a maximum of 8 links to 12, revealing more about the websites you are searching for. - Sitelink ranking is now also combined with regular result ranking to produce higher quality searches. - Sitelinks also vary based on your query, where a more comprehensive keyword search will return better results.
This basically means more power to the top 1-2 results if they use sitelinks, as they grab more above-the-fold space. This will increase the need for a SEO strategy that will get your site on the top spot of the desired keywords / phrase (and of course refuel the discussion on whether this is a good move as it will be slightly harder for users to see a more diverse choice of results)
More at The evolution of sitelinks: expanded and improved - Official Google Blog and Google improves sitelinks for better search results - The Next Web